In the recent broadcast and communication environment, network data congestion has significantly increased due not only to the increase in a variety of multimedia content, but also to the increase in high-capacity content such as High Definition (HD) content or Ultra High Definition (UHD) content. Due to these circumstances, the content sent by a sender (for example, a host A) may not be normally delivered to a receiver (for example, a host B). For example, some of the content may be lost in the transmission route of a channel or the network. In many cases, since data is transmitted in packets (or in units of packets), data loss may also occur in packets. Due to the data loss in the network, the receiver may not receive data packets, so the receiver may not determine the data in the lost packets. In turn, this may cause various types of user inconveniences such as degradation of audio, degradation of video, image distortion, subtitle missing, and file loss. For this reason, there is a need for technology for repairing (or recovering) the data lost in the network.
One technology for allowing a receiver to repair the data lost in the network configures (or constructs) a source block with a predetermined number of data packets, which are called source packets and may have different lengths, and adding repair information such as parity data or repair packet to the source block by Forward Error Correction (FEC) encoding. If there is lost data, the receiver may perform decoding using the repair information.
As for each of the source packets to which the repair information is attached, a source packet whose length is not a desired value may undergo zero padding. In other words, the existing structure of a source block is likely to include a significant amount of zero padding depending on the length of the packets. The zero-padded data is a meaningless value that is not transmitted by the sender, but it has an impact on the increase in the number of symbols constituting the source block and is involved in making parity data, actually causing the same effect as generating and transmitting the parity for unnecessary information.
By reducing the desired length of the source packets to solve these problems, the amount of zero padding may be reduced. In this case, however, as the number of symbols constituting the source block may significantly increase, FEC codes of a very long length may be required. The length of FEC codes that can be used in the system is limited, and as the length of codes is longer, the complexity may significantly increase during Maximum log-Likelihood (ML) decoding, causing an increase in decoding latency.
Therefore, there is a need for an efficient source block configuration method capable of reducing the number of encoding symbols and improving the error correction capability by reducing zero-padded data, and for technology capable of allowing a receiver to efficiently repair the lost data using the received source packets and repair packets.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.